AJP - Heart and Circulatory Physiology, Vol 258, Issue 3 773-H777, Copyright © 1990 by American Physiological Society
Brachial artery diameter changes associated with cardiopulmonary baroreflex activation in humans
G. M. London, B. M. Pannier, S. Laurent, P. Lacolley and M. E. Safar
Department of Internal Medicine and Hypertension Research Center, Broussais Hospital, Paris, France.
Stimulation of receptors in the cardiopulmonary compartment produces a
vasodilatation of forearm resistive vessels. A possible participation of
large conduit arteries in such adjustments, studied in situ, has not been
clearly documented in humans. We used a dual-crystal pulsed Doppler system
to determine whether leg elevation in recumbent subjects is associated with
changes in brachial artery diameter (BAD) and blood velocity (BV) in
humans. BA diameter, velocity, and flow, together with arterial pressure
and heart rate, were measured in 20 normal subjects in supine position and
after passive leg raising. BAD increased immediately after leg elevation
from 4.03 +/- 0.11 to 4.56 +/- 0.13 mm (P less than 0.001) parallel with an
increase in BV from 6.05 +/- 1.18 to 7.1 +/- 1.36 cm/s (P less than 0.02).
A positive correlation between BAD enlargement and BV increase was observed
during the initial peak response (P less than 0.01). Subsequent measures
indicated that BAD remained enlarged throughout the whole period of leg
raising, whereas BV returned to the base-line values. Brachial artery
volumic flow augmented during the initial phase of leg raising from 46 +/-
8 to 74 +/- 15.5 ml/min (P less than 0.01) and remained elevated throughout
the whole period of leg elevation. This study shows that arteries
participate in hemodynamic adjustments induced by positional changes
associated with cardiopulmonary baroreflex activation.
